The present invention relates to an adaptive cruise control system. It finds particular application in conjunction with avoiding a fault condition of the adaptive cruise control system and maintaining braking based on the vehicle acceleration response and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
It is becoming more common for heavy vehicles to include standard cruise control technology. Recent developments in cruise control technology have resulted in systems, commonly referred to as adaptive cruise control (ACC) systems, which are capable of measuring and maintaining a substantially constant following distance or headway distance relative to a forward vehicle. ACC systems in North America are typically programmed for passenger automobiles. For heavy vehicle applications, additional settings include “torque limiting” and “delayed braking.” Vehicle acceleration when driving downhill must be monitored and braking response maintained.
It has become desirable to modify heavy vehicles that currently include the standard cruise control technology to also include ACC systems. An ACC system adapted from a passenger car model may cause a fault to be set when used on heavy vehicles. For example, the substantially higher mass of heavy vehicles, relative to passenger cars, causes a higher rate of downhill acceleration. When ACC is requesting deceleration of the vehicle and the vehicle deceleration does not adequately respond to the ACC request, then an issue with the system will be identified and a fault will be set.
In some vehicles, once a fault is set, the cruise control and ACC systems are disabled until the fault is cleared. Clearing the cruise control and ACC systems faults is typically a cumbersome and time consuming process that, for example, may require shutting-down and re-starting the vehicle engine.
The present invention provides a new and improved apparatus and method which addresses the above-referenced problems.